Eur. Phys. J. E (2009) 30: 333-340
https://doi.org/10.1140/epje/i2009-10525-4

Regular Article

Criticality in a non-equilibrium, driven system: Charged colloidal rods (fd-viruses) in electric fields

Forschungszentrum Jülich, Institute für Festkörper Forschung (IFF), Weiche Materie, D-52425, Jülich, Germany

^* e-mail: k.kang@fz-juelich.de

Received: 22 April 2009
Revised: 10 July 2009
Accepted: 25 September 2009
Published online: 27 October 2009

Abstract

Experiments on suspensions of charged colloidal rods (fd-virus particles) in external electric fields are performed, which show that a non-equilibrium critical point can be identified. Several transition lines of field-induced phases and states meet at this point and it is shown that there is a length- and time-scale which diverge at the non-equilibrium critical point. The off-critical and critical behavior is characterized, with both power law and logarithmic divergencies. These experiments show that analogous features of the classical, critical divergence of correlation lengths and relaxation times in equilibrium systems are also exhibited by driven systems that are far out of equilibrium, related to phases/states that do not exist in the absence of the external field.